表达牛源犬新孢子虫NcSRS2基因重组腺病毒的构建及免疫原性分析

为构建牛源犬新孢子虫NcSRS2基因重组腺病毒,并分析其免疫原性,PCR扩增牛源犬新孢子虫NcSRS2基因,构建克隆质粒pMD18-T-NcSRS2、重组腺病毒穿梭质粒pCR259-NcSRS2及表达质粒Transpose-AdNcSRS2,脂质体介导转染QBI-HEK293细胞,包装重组腺病毒Ad5-NcSRS2,PCR检测重组腺病毒NcSRS2基因,IFAT和Western blotting检测NcSRS2基因在QBI-HEK293细胞中的表达,测定病毒滴度后,收集病毒液免疫BALB/c小鼠,间接ELISA检测小鼠血清IgG抗体水平.结果显示,扩增的牛源犬新孢子虫NcSRS2基因大小为1 227 bp,与GenBank中发表的NcSRS2( AF061249)核苷酸序列相似性为99％；重组腺病毒Ad5-NcSRS2在293细胞中包装成功,表达蛋白的相对分子质量为43 ku,具有较好的反应原性；测得重组腺病毒Ad5-NcSRS2滴度为109TCID50·mL-1,间接ELISA检测二免后3周BALB/c小鼠血清中IgG抗体效价达1 ∶ 2 048.本研究成功构建了具有良好免疫原性的重组腺病毒Ad5-NcSRS2,为牛源犬新孢子虫NcSRS2基因重组腺病毒载体疫苗的研制奠定了基础.

Construction of a Recombinant Adenovirus Expressing NcSRS2 Protein of Bovine Neospora Caninum and Immunogenicity Analysis of the Protein

In order to construct a recombinant adenovirus expressing NcSRS2 protein of bovine Neospora Caninum,NcSRS2 gene of bovine Neospora Caninum was amplified by PCR,pMD18-T-NcSRS2,pCR259-NcSRS2 and Transpose-Ad-NcSRS2 were constructed in this research.Coated with liposome,Transpose-Ad-NcSRS2 was transfected into QBI-HEK293 cells to package recombinant adenovirus Ad5-NcSRS2.Recombinant adenovirus NcSRS2 gene was detected by PCR.The expression of NcSRS2 gene in QBI-HEK293 cells was detected by IFAT and Western blotting.After the virus titer was determined,the virus fluid was collected to inoculate BALB/c mice and IgG antibody levels in the sera were measured by indirect ELISA.The size of NcSRS2 gene was 1 227 bp.The nucleotide sequence of the gene shared 99% homology with that in GenBank(AF061249).Recombinant adenovirus Ad5-NcSRS2 was successfully packaged in 293 cells.The protein expressed by Ad5-NcSRS2 was 43 kD and had good reactogenicity.The titer of recombinant adenovirus Ad5-NcSRS2 was 109TCID50·mL-1.Three weeks post the second immunization,IgG antibody titers in the sera of BALB/c mice were up to 1:2 048,measured by indirect ELISA.A recombinant adenovirus Ad5-NcSRS2 which have good immunogenicity was successfully constructed.This settles a solid foundation for the development of recombinant adenovirus vaccine against Neospora Caninum based on NcSRS2 gene.